"Our 4G LTE network is up and running. Our network engineers and vendors quickly identified the issue and solved it," a spokesperson said in a statement.
Laptop users with USB modems may need to reconnect to the network when moving between 3G and 4G, he added. "This will continue to improve."
On Wednesday afternoon Verizon acknowledged problems with its 3G and 4G LTE networks. The nationwide outage also prevented any new LTE device activations, most notably the HTC Thunderbolt, the only smartphone so far available on Verizon's super high-speed 4G network.
An HTC spokesperson said he was not aware of any negative effect on sales during the outage, and a Verizon spokesperson declined to comment.
During an earnings call last week, Verizon said it had more than half a million subscribers for its LTE network. Furthermore, since March 17, Verizon has sold more than 260,000 HTC Thunderbolt devices, the first smartphone available for LTE. The smartphone is one of ten 4G LTE devices Verizon announced at CES in January.
Earlier this month, Verizon iPad 2 owners also complained of connectivity issues related to the ability to switch from Wi-Fi to Verizon 3G.
Since launching in December, Verizon has expanded its 4G LTE network to 39 cities around the country, and planned to add another 59 cities by the end of the year. 4G LTE boasted theoretical download speeds of 5 to 12 Mbps and upload speeds of 2 to 5 Mbps.
To learn more about the Android 2.2-based smartphone, see PCMag's review of HTC Thunderbolt.